Fatty-acid spin probe interactions with erythrocyte ghosts and liposomes prepared from erythrocyte ghosts

Abstract

A model for the binding of 5-nitroxide stearate, I(12.3), to human erythrocyte ghosts was developed by comparing spin probe interactions with ghosts and liposomes prepared from ghosts. At low probe/lipid (P/L less than 1/2500), I(12.3) binds to a similar class of high-affinity, noninteracting sites in both ghosts and liposomes, indicating that lipid moieties are responsible for probe uptake. Saturation occurs in both systems with increasing P/L, and, at higher loading (e.g., P/L = 1/360 for ghosts and liposomes), the probe inserts itself at initially dilute sites to form a class of low-affinity sites consisting of clusters of variable size. At still higher P/L ranges (greater than 1/100), much increased probe uptake was observed in ghosts than in liposomes, which was attributed to another class of low-affinity sites, representing nonspecific interactions of I(12.3) with membrane proteins. The nature of the spectral components and ultrafiltration experiments with ghosts labeled at high P/L indicate that both 'dilute' and 'clustered' I(12.3) are due to membrane-incorporated probe.

Neutrophil-mediated oxidative stress and albumin structural damage predict COVID-19-associated mortality

“…Ethanolic solutions (0.02 M) of the spin labels were added to the blood/plasma in the ratio 1:100 and the cells were measured at 37°C. From the spectrum of 5-DSA an order parameter (S) was derived by measuring the outer and inner hyperfine splitting 2T ‖ and 2T ⊥ as defined in Figure 1 ( Gordon et al, 1989 ; Marczak et al, 2006 ) using the formula: …”

Interaction of doxorubicin and idarubicin with red blood cells from acute myeloid leukaemia patients

“…Ethanolic solutions (0.02 M) of the spin labels were added to the erythrocytes in the ratio 1:100 and the cells were incubated for 30 min at 37 C. From the spectrum of 5-DSA ( Fig. 1a) an order parameter (S ) was derived by measuring the outer and inner hyperfine splitting 2T k and 2T t (Gordon et al, 1989) using the formula:…”

The effects of imidazoacridinones, new antineoplastic agents, on the human erythrocyte membrane

“…The spectra were recorded at room temperature. In the present study, the membrane fluidity near the polar groups was estimated by the order parameter, S, according to Gordon et al (14). The lipid fluidity in the internal hydrophobic core of the lipid bilayer was measured in the presence of 16-DSA using an empirical parameter, the ratio of signal height, ho/h.l.…”